Can't import diagram Purchase Order Validation (BPMN process diagram) on Bonita 6.4.2
You need to download the version for the applicable piece of Bonita you have, COMMUNITY or SUBSCRIPTION.
However you are right the documentation is unclear, maybe Bonita could make this clear on the download page rather than making us work for it.
COMMUNITY EXAMPLE works with 6.0.4 upwards (tested with 6.5.0 successfully)
The version you downloaded Purchase Order Validation (BPMN process diagram) I think only works with 5.x
I also got the same "You are trying to import a process who has been designed with an incompatible version." when trying to use a Community Edition to import a .bos file that was exported using a Subscription Edition.
Is there a way to get that file imported instead of having to recreate the diagrams?
No you can't import in Community Edition a diagram created with Subscription Edition. That's because Subscription Edition includes additional features not available in Community Edition.